In electrical inspection of, for example, wafers, on which a great number of integrated circuits have been formed, or circuit devices of electronic parts such as semiconductor devices, a probe device having inspection electrodes arranged in accordance with a pattern corresponding to a pattern of electrodes to be inspected of a circuit device to be inspected is used. As such a probe device, may be used that, on which inspection electrodes (inspection probes) each composed of a pin or blade are arranged.
When the circuit device to be inspected is a wafer, on which a great number of integrated circuits have been formed, it is however necessary to arrange a very great number of inspection probes upon production of a probe device for inspecting the wafer, so that such a probe device becomes extremely expensive. In addition, when the pitch of electrodes to be inspected is small, the production of the probe device itself becomes difficult. Further, since warpage generally occurs on wafers, and the condition of the warpage varies with individual products (wafers), it is difficult in fact to stably and surely bring inspection probes of the probe device into contact with a great number of electrodes to be inspected on the wafer, respectively.
For the above reasons, in recent years, there has been proposed a probe card comprising a circuit board for inspection, on one surface of which a plurality of inspection electrodes have been formed in accordance with a pattern corresponding to a pattern of electrodes to be inspected, an anisotropically conductive sheet arranged on one surface of the circuit board for inspection, and a sheet-like probe arranged on the anisotropically conductive sheet and obtained by arranging, in an insulating sheet, a plurality of electrode structures each extending through in a thickness-wise direction of the insulating sheet (see, for example, the following Prior Art. 1 and Prior Art. 2).
The sheet-like probe in such a probe card is specifically described. As illustrated in FIG. 42, this sheet-like probe 90 has a flexible circular insulating sheet 91 composed of, for example, a resin such as polyimide. In this insulating sheet 91, a plurality of electrode structures 95 extending in a thickness-wise direction of the sheet are arranged in accordance with a pattern corresponding to a pattern of electrodes to be inspected of a circuit device to be inspected. Each of the electrode structures 95 is formed by integrally connecting a projected front-surface electrode part 96 exposed to a front surface of the insulating sheet 91 and a plate-like back-surface electrode part 97 exposed to a back surface of the insulating sheet 91 to each other through a short circuit part 98 extending through in the thickness-wise direction of the insulating sheet 91. In addition, a ring-like holding member 92 composed of, for example, a ceramic is provided at a peripheral edge portion of the insulating sheet 91. This holding member 92 serves to control thermal expansion of the insulating sheet 91 in a plane direction thereof, thereby preventing positional deviation between the electrode structures 95 and the electrodes to be inspected by temperature changes a burn-in test.
However, such a sheet-like probe involves the following problems.
On a wafer, for example, having a diameter of at least 8 inches, at least 5,000 or 10,000 electrodes to be inspected are formed, and a pitch between the electrodes to be inspected is 160 μm or less. As a sheet-like probe for conducting inspection of such a wafer, it is necessary to use that having a large area corresponding to the wafer and at least 5,000 or 10,000 electrode structures arranged at a pitch of 160 μm or less.
The coefficient of linear thermal expansion of a material forming the wafer, for example, silicon is about 3.3×10−6/K, while the coefficient of linear thermal expansion of a material forming the insulating sheet in the sheet-like probe, for example, polyamide is about 4.5×10−5/K. Accordingly, when a wafer and a sheet-like probe each having a diameter of, for example, 30 cm at 25° C. are heated from 20° C. t 120° C., the change in diameter of the wafer is theoretically only 99 μm, while a change in diameter of the insulating sheet in the sheet-like probe reaches 1,350 μm, so that a difference in thermal expansion between the same is 1,251 μm.
When a great difference in the absolute quantity of thermal expansion in a plane direction is caused between the wafer and the insulating sheet in the sheet-like probe as described above, it is difficult to surely prevent positional deviation between the electrode structures and the electrodes to be inspected by temperature changes in the burn-in test even when the peripheral edge portion of the insulating sheet is fixed by the holding member having a coefficient of linear thermal expansion equivalent to the coefficient of linear thermal expansion of the wafer, so that a good electrically connected state cannot be stably retained.
In addition, even when the object of inspection is a small-sized circuit device, it is difficult to surely prevent positional deviation between the electrode structures and the electrodes to be inspected by temperature changes in the burn-in test when a pitch between the electrodes to be inspected is 50 μm or less, so that a good electrically connected state cannot be stably retained.
In order to solve such a problem, Prior Art. 1, identified hereinafter, proposes a means for relaxing the thermal expansion of the insulating sheet by fixing the insulating sheet to the holding member in a state tension has been applied to the insulating sheet.
However, in such a means, it is extremely difficult to evenly apply the tension to the insulating sheet in all directions of the plane direction thereof and a balance of the tension applied to the insulating sheet is changed by forming the electrode structures. As a result, the insulating sheet comes to have anisotropy on thermal expansion, so that even when the thermal expansion in one direction of the plane direction can be inhibited, thermal expansion in other directions intersecting said one direction cannot be inhibited. After all, the positional deviation between the electrode structures and the electrodes to be inspected by temperature changes cannot be prevented.
In addition, in order to fix the insulating sheet to the holding member in the state that the tension has been applied thereto, a complicated step of bonding the insulating sheet to the holding member under heating is required, so that a problem that increases in production cost is incurred arises.
Prior Art. 1: Japanese Patent Application Laid-Open No. 2001-15565;
Prior Art. 2: Japanese Patent Application Laid-Open No. 2002-184821.